1

I have a PC speaker with it's owner power supply (no amplifier needed). It just uses a standard AUX jack.

Most examples sketches use an amplifier like the MAX98357A. I have explored some libraries too, such as ESP8266Audio.

I just want to find a simple example that emits audio (not just noise). This is my setup:

enter image description here

enter image description here

I thought an audio program would use the internal DAC to create the CODEC? Or am I not understanding something?

const int  DAC_CH1 = 25; // or 26

void setup() 
{
//    dacWrite(DAC_CH1, 255); // ~3v3
//  dacWrite(DAC_CH1, 192); // ~2.5
//  dacWrite(DAC_CH1, 128); // ~1.7
}

void loop(){}

Edit

I found the PlayMODFromPROGMEMToDAC example, which uses pin 25 DAC:

#include <Arduino.h>
#include "AudioFileSourcePROGMEM.h"
#include "AudioGeneratorMOD.h"
#include "AudioOutputI2S.h"
#if defined(ARDUINO_ARCH_RP2040)
    #define WIFI_OFF
    class __x { public: __x() {}; void mode() {}; };
    __x WiFi;
#elif defined(ESP32)
    #include <WiFi.h>
#else
    #include <ESP8266WiFi.h>
#endif

// enigma.mod sample from the mod archive: https://modarchive.org/index.php?request=view_by_moduleid&query=42146
#include "enigma.h"

AudioGeneratorMOD *mod;
AudioFileSourcePROGMEM *file;
AudioOutputI2S *out;

void setup()
{
  WiFi.mode(WIFI_OFF); //WiFi.forceSleepBegin();
  Serial.begin(115200);
  delay(1000);

  audioLogger = &Serial;
  file = new AudioFileSourcePROGMEM( enigma_mod, sizeof(enigma_mod) );

   /* HERE! */
   // ↓
   // ↓
   out = new AudioOutputI2S(0, 1); //Uncomment this line, comment the next one to use the internal DAC channel 1 (pin25) on ESP32
   // ↑
   // ↑
//  out = new AudioOutputI2S();
  mod = new AudioGeneratorMOD();
  mod->SetBufferSize(3*1024);
  mod->SetSampleRate(44100);
  mod->SetStereoSeparation(32);
  mod->begin(file, out);
}

void loop()
{
  if (mod->isRunning()) {
    if (!mod->loop()) mod->stop();
  } else {
    Serial.printf("MOD done\n");
    delay(1000);
  }
}

Although, still no sound (besides noise) can be heard.

3
  • no need for DAC ... toggle a digital pin
    – jsotola
    May 10, 2023 at 18:49
  • What do you mean by "audio not just noise"? Can't you simply toggle the pins? An alternative would be to use the sin() function to generate a "clean" note. May 11, 2023 at 5:59
  • Ideally something like talkMIDI(0xC0, instrument, 0) as found here: sparkfun.com/tutorials/302
    – adamaero
    May 11, 2023 at 13:50

0

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